Meson correlators in the epsilon-regime of two-flavor lattice QCD

We calculate the meson correlators in the $ϵ$-regime of two-flavor QCD. On a ${16}^3\times 32$ lattice with $a\sim 0.11$ fm, the lattice simulations are performed with the dynamical overlap fermions. We reduce the sea quark mass down to $\sim$ 3 MeV and the valence quark masses are taken in the range 1-4 MeV. The meson correlators in various channels are compared with the predictions of (partially quenched) chiral perturbation theory (ChPT). Including the NLO order of the $ϵ$-expansion, we extract the leading-order low energy constants of ChPT, the pion decay constant $F$ and the chiral condensate $\mathrm{\Sigma }$, as $F=87.3(5.5)$ MeV and ${\mathrm{\Sigma }}^{\overline{\mathrm{M}\mathrm{S}}}=[237.8(4.0)MeV{]}^3$.